If your gonna put 12:1 pistons in your engine why not just use longer rods and do some what of a stroker kit. Lenghten the stroke and you will get more displacement if im not mistaken. 86MM is a pretty big piston for a B18a engine. Im not sure what kind of displacement you would get from that, all depends of you use stock lenght rods or not with the pistons assuming your gonna upgrade to forged rods with pistons with that high of a CR and that big of a bore size.